3AG 3 Glass Cartridge Fuse - Equivalent & Substitute Parts

Part Overview

The 3AG 3 is a 3 A, 250 V AC/DC fast-blow glass cartridge fuse manufactured by Bel Fuse Inc. This component is classified as obsolete, requiring identification of active equivalent alternatives for new designs and ongoing maintenance applications. The 3AG form factor (1/4" x 1-1/4") is a standard cartridge fuse package widely used in industrial and consumer electronics requiring overcurrent protection in AC and DC circuits.

Substiute Parts

3AG 3

Bel Fuse Inc.In Stock: 10953AG 3 Datasheet

Current PartRFQ

3AG 3-R

Bel Fuse Inc.In Stock: 128293AG 3-R Datasheet

DirectRFQ

0312003.MXP

Littelfuse Inc.In Stock: 123840312003.MXP Datasheet

SimilarRFQ

0034.5135

SCHURTER Inc.In Stock: 10320034.5135 Datasheet

Parametric EquivalentRFQ

FSA-3A

OptiFuseIn Stock: 11529FSA-3A Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict equivalence across the following parameters:

• Current Rating: 3 A (exact match required)
• Voltage Rating: 250 V AC (exact match required)
• Fuse Type: Cartridge, Glass (exact match required)
• Response Time: Fast Blow (exact match required)
• Package / Case: 3AB, 3AG, 1/4" x 1-1/4" (exact match required)
• Mounting Type: Requires Holder (exact match required)
• Operating Temperature Range: -55°C to 125°C (minimum requirement)

All substitute parts listed meet these core electrical and mechanical parameters. Variations in breaking capacity, melting I²t, DC cold resistance, and compliance certifications are noted but do not disqualify substitution where the primary parameters align.

Parameter Comparison

Engineering Selection Recommendations

For new designs and active production environments, 3AG 3-R (Bel Fuse Inc.) is the primary direct replacement. This part maintains identical electrical and mechanical specifications to the original 3AG 3 while offering active product status and ROHS3 compliance.

For applications requiring alternative manufacturers, 0312003.MXP (Littelfuse Inc.) and FSA-3A (OptiFuse) are functionally equivalent substitutes with active product status and ROHS3 compliance. Both parts meet all core electrical parameters and package requirements. Note that these alternatives specify lower breaking capacity (100 A versus 200 A) and different melting I²t values; verify circuit protection requirements before selection.

The 0034.5135 (SCHURTER Inc.) is electrically equivalent but carries obsolete product status, limiting its suitability for new applications despite ROHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can 3AG 3-R directly replace the obsolete 3AG 3?

A: Yes. The 3AG 3-R maintains identical current rating (3 A), voltage rating (250 V AC), response time (fast blow), and package dimensions (1/4" x 1-1/4"). Both require the same 3AB/3AG holder. The primary difference is product status (active versus obsolete) and RoHS compliance.

Q: What is the difference between the 200 A and 100 A breaking capacity ratings?

A: Breaking capacity defines the maximum fault current the fuse can safely interrupt without rupturing the fuse body or holder. The 3AG 3 and 3AG 3-R specify 200 A breaking capacity, while 0312003.MXP and FSA-3A specify 100 A. For circuits with fault currents exceeding 100 A, the higher breaking capacity variants are required.

Q: Are all substitute parts compatible with existing 3AB/3AG holders?

A: Yes. All listed substitutes use the identical 3AB/3AG cartridge holder package and 1/4" x 1-1/4" form factor. Physical installation compatibility is guaranteed.

Q: What does ROHS3 compliance mean for this fuse?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. The original 3AG 3 is non-compliant; all active substitutes are ROHS3 compliant.

Q: Does melting I²t variation affect substitution suitability?

A: Melting I²t represents the thermal energy required to melt the fuse element. Variations (14 to 23.12 across substitutes) reflect different fuse element designs but do not disqualify substitution where current and voltage ratings match. Verify circuit protection coordination if precise I²t matching is required.

Q: Which substitute offers the best long-term availability?

A: 3AG 3-R (Bel Fuse Inc.) and FSA-3A (OptiFuse) both carry active product status with substantial inventory levels (12,754 and 11,500 units respectively), indicating strong long-term availability.